The purpose of the Immunocytochemistry and Islet Isolation Core Facility is to fold: 1) to make available to the team of the Project a variety of immunocytochemical techniques for the analysis of cells and tissues with state of the art technology; 2) to supply the individual investigators with freshly isolated pancreatic islets from ice. The facility will offer technical and scientific expertise for immunocytochemical studies using conventional and confocal light microscopy as well as provide services in cryomicrotomy and immuncytochemistry for the histological analysis of tissues and cell lines from normal and trangenic animals. These techniques will be applied to the study of proteins such as MHC molecules, T cell receptors, cytokines, and beta-cell utoantigens, including GAD, insulin and ICA512. Routine isolation of freshly pancreatic islet cells from NOD and transgenic mice will be required for generating and maintaining islet- specific T cell clones. A centralized facility has the advantage of assuring that islets for the different projects are prepared using standardized and up-to-date procedures.